Used in solid-phase oligonucleotide synthesis as a phosphoramidite building block for incorporating deoxycytidine residues into DNA strands. The 4,4'-dimethoxytrityl (DMT) group protects the 3'-hydroxyl during chain assembly and allows for monitoring of coupling efficiency. The diisopropylamino and cyanoethoxy groups stabilize the phosphite intermediate and facilitate activation under mild acidic conditions. The N-benzoyl moiety protects the exocyclic amine of cytosine, preventing side reactions. After each coupling step, the DMT group is removed, and the cycle continues, enabling the stepwise construction of custom DNA sequences for applications in molecular biology, genomics, and diagnostic probe development.